A fastening strap is frequently connected to an object, such as a diving mask, a pair of swimming goggles, a fin, or a pair of snow goggles, for tightly holding the object to a wearer. Generally, the fastening strap is connected to and between two opposite ends of the object and is adjustable in tightness, allowing the object to be comfortably worn on the wearer's body area, such as the wearer's head or feet, to where the object is fitted.
Conventionally, the fastening strap is usually integrally formed using an elastic material, such as silicon rubber or rubber. Two opposite free ends of the fastening strap are movably extended through, for example, two buckles connected to two opposite ends of the object and turned back to be held to the buckles. By pulling the turn-back free ends of the fastening strap, the tightness of the object against the wearer's body area can be adjusted.
The above conventional fastening strap has the disadvantages of inconvenient to handle, uneven tightness, and tending to interfere with other nearby devices. Among others, Taiwan Patent Publication No. 239925 discloses an improved fastening strap, which includes a curved assembling plate, two straps, and two push plates. The curved assembling plate is provided on an outer surface near two opposite ends with two laterally symmetrical slots, and two opposite ends of the curved assembling plate are formed into two open entrances equipped with a shaft each. The curved assembling plate is provided at predetermined positions with retaining holes for engaging with retaining hooks provided on the push plates. The straps are made of an elastic material to thereby provide a certain degree of lengthwise elasticity. Each of the straps is provided with a plurality of non-return retaining teeth protruded from an outer surface of the strap. The non-return retaining teeth allow the straps under pressure to be pulled outward but stop the outward pulled straps from retracting reversely. The straps are movably connected at respective fixing ends to two opposite sides of a frame of an object. The free ends of the straps are separately extended through the two slots on the curved assembling plate to wind around the shaft each before being outward turned back to expose from an outer side of the assembling plate to form two turn-back sections. Meanwhile, the non-return retaining teeth on the straps passing the shafts are stuck at the shaft. The push plates are connected to the curved assembling plate through engagement of the retaining hooks on the push plates with the retaining holes on the curved assembling plate. The push plates are of an elastic structure, so that outer sections or operating sections of the push plates can be compressed inward and elastically extend outward, allowing the push plates to be elastically pulled. A raised non-return retaining rib having similar structure as the non-return retaining teeth on the straps is provided on an inner side of the operating section of each of the two push plates for controlling the tightening and the loosening of the turn-back sections. With these arrangements, the fastening strap disclosed in Taiwan Patent Publication No. 239925 can be more easily adjusted to different levels of tightness, compared to other conventional fastening straps.
However, the following disadvantages are found in the fastening strap disclosed in
Taiwan Patent Publication No. 239925:    (1) The two turn-back sections are exposed from the curved assembling plate to result in an unpleasant appearance and tend to tangle with other objects to adversely affect the smooth installation and operation of other nearby devices; and    (2) Particularly, the two turn-back sections are separately oriented to two opposite directions, and a user has to pull the two turn-back sections with two hands in two opposite directions in order to tighten the straps. That is, the two turn-back sections could not be handled with only one hand. Therefore, for a user, such as a diver, who usually holds some other device, such as a diving torch, with one hand, it would be inconvenient or even difficult to operate the turn-back sections with two hands to adjust the tightness of the straps.